Boiler Noise 1

It is amazing how many problems faulty heating and cooling equipment can make especially if it makes a lot of different kinds of noises! Also amazing how many words people can use to describe them.

Below you can see a list of noises and sounds people usually use to describe a noise that is coming from their furnaces, heat pumps, air conditioners and boilers:

Back peddling, banging, booming, buzzing noise, chattering, chirping, clacking, clanging, clicking, droning, explosion, grating, grinding, groaning, grumbling sound, gurgling, hammering, high pitched, high pitched whine, high pitched whistle, hissing, howling, humming, knocking, metal hitting metal, moaning noise, out of balance washing machine, plane engine, popping, pulsating, random, ratcheting, rattling, roaring, rumbling, scraping, screech, screeching, siren, sputtering, squeaky, squealing, switching, swoosh, thumping, ticking, tinny, train like, vibration, weird, whining, whirring, whooshing, wobbling, woof noises or sounds.

Some people have a hard time to describe what kind of noise coming from their units, for example:
Furnace is making a loud noise, awful furnace motor noise, furnace noise reduction, gas furnace noise like a slamming door that vibrates, heat pump making funny noise, when I turn on furnace sound strange, our boiler makes noises through the whole house and so on!
If you one of them, please carefully read through all lists of noises and try to find one that describes yours.

Currently, on my site, I have six pages dedicated to these kinds of issues and they are all made the same way:
At the top of the module, you can see a short list of noises. If you click on any word from the list, which in your opinion better describes your type of noise, the page is going to jump down and you can read the question and the answer to that question or feedback written by a person who asked that question in the first place.
If you cannot find the type of noise, you are looking for or if there are several questions with the same type of noise just scroll down to the next module or go to the next page.

List of the pages:

Furnace/Air Handler Noise
Furnace/Air Handler Noise 2
Furnace/Air Handler Noise 3
Heat Pump Noise
Heat Pump Noise 2
Boiler Noise
Boiler Noise 2
Boiler Noise 3
Air Conditioner Noise

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List of Noises 1:

Banging noise 1
Banging noise 2
Buzzing noise 1 Buzzing noise 2

Question
Loud bangs in boiler pipes, major fluctuations in pressure.
I have an old Weil-McLain floor model boiler I'm not sure of the model but if it helps it's about 30-40 years old, it 31" tall and is gray/blue in color; is natural gas fired. It also runs 3 zones with copper tube/aluminum fin baseboard radiators. My zones are basement, first floor, and second floor. My home is a two story wood frame house about 50+ years old.

Last year my pump gave me some trouble but got through the season. My zone valves also took some maintenance. They were old Dole HM2-3/4 zone valves.

I just finished replacing the circulation pump. The pump was the recommended replacement. The old pump was a 15-42F and the new one is a 15-58FC. I also installed 3 new Taco E075C2-3 zone valves. I also installed a new Honeywell Fv180 air vent. This air vent sits directly on top of the boiler. I also installed a new pressure temp gauge, which is on the side next to the pressure relief valve.

After I completed installing the new parts I first bleed the system with the zone valves open but without the pump running. I then bleed it with the pump running. I have also now bled the system hot. For clarification by bleeding, I mean that I have gone to each zone and opened the bleed valves until no air was evident. Some time this meant many bucketfuls of water. I also opened the cap on the new bleed valve on top of the boiler.

My problem now it's that the pipes near the boiler bang (like a hammer hitting them) and my pressure wildly fluctuates 5-20 PSI. My pressure will also build from 10 up to as much as 30 then my relief valve pops.

After the burners go off the air valve will then hiss like a pressure cooker for about 1 minute.

I initially had my accumulator tank set at 17 PSI but I was getting regular relief valve pop offs. I then lowered it to 10 and it helped. This has been going on for 4 days.

What am I missing here?

Answer
While the tank may in fact be pouched, I doubt that's what's making the gremlins inside the boiler get out their hammers. Sounds more like there's not enough water in the system, maybe the pump is backwards... or possible cavitations...
On the expansion tank... that appears to be a FILL-TROLL tank and valve. You can't just replace that with a standard tank.
                                                                                                                                                                           
Feedback
Fixed! Thanks to everyone. My pump was in upside down!.
The new pump looks nearly identical to the old one so I assumed (you know what happens when you assume?) it was the same direction of flow. I turned it over, drained about a cup of water out of the Fill-Troll tank, then set it's pressure; bled it out, and now it's working better than I ever known it to.
Thanks again. Now I enjoy a quiet, smooth running system.
                                                                                                                                                                           
Question
My forced hot water boiler is making a banging sound or booming sound, what should I do?

Answer
The (banging) noise is most likely due to your boiler running low on water or having no water at all in. Do not attempt to fill your hot boiler with cold water, you will crack the block and need a new boiler. This could mean your automatic fill is not doing its job and needs to be looked at.
                                                                                                                                                                          
Question
My 50 year old boiler is making a loud buzzing sound from an electric box on the front of the boiler. When I open up the box (approx 5"x5") there are some wires, and what looks like a small electric motor. Attached to the motor is what looks like a tiny metal square that is vibrating to make the noise.
It is pretty loud. There is no labeling, writing, or marking to tell me what this part of the boiler is. Any ideas?

Answer
What you describe sounds like a contactor. This is what is used to switch on and off the power to your boiler. Contactors are nothing more than high voltage switches controlled by low voltage conductors. Contactors are used to reduce arcing when equipment is switched on and off. When the low voltage conductors that are being fed by the thermostat have voltage applied to them they create an electromagnet around the square piece (coil) you described. Somewhere on this square coil should be a set of contacts that are pulled closed by magnetic force when the low voltage control wires are energized. The use of electromagnets causes the contacts to engage and disengage much faster than a human finger can flip a switch, thus reducing arcing as the contacts are pulled together and separated. Now, to fix your problem.(hopefully) This is what I think you should try. Turn off the power to this contactor (high and low voltage). Once power is off, take some emery cloth or very fine sand paper and gently buff the contact points until all burn residue is removed. The buzzing you hear is most likely caused by insufficient contact caused by this residue. Put it all back together and turn back on. If the problem persist, then you will need to replace the contactor.

A boiler banging noise can be very disconcerting whether you are a new home owner or have lived in the house for a very long time. A banging noise from the boiler is not necessarily the first sign of a larger problem; however, it is a sign that your boiler system needs some attention. There are many reasons why your boiler or pipes will begin to make noises and the reason(s) why will need to be thoroughly investigated.
The number one reason why you will hear a boiler knocking sound is air build up in the system. Through the process of adding water to the system air will naturally accumulate in your boiler system and pipes. Find the bleeder (or pressure release) valve for your system and slowly let the air escape the system. You will probably hear a hissing noise as the air escapes the system. This should eliminate the banging sound if it is the sole cause of your problem.
Another issue that can lead to banging noises from your boiler is sediment build up in your system. As the sediment settles on the bottom of the tank, when the heating element begins to heat the water, it is blocked by the hard crust of sediment and this will lead to rapid heating of the water, which in turn, creates steam in the system and the banging noises that you are hearing.
Another cause of banging noises from your boiler is a faulty expansion tank or a fast closing zone valve. If either of these parts is not functioning properly they will either need to be repaired or replaced. Replacing or repairing a boiler expansion tank or zone valve is a job best left to a professional. If you believe that this is the cause of your problems, call a service technician to properly diagnose and repair your boiler system.                                                                                 

List of Noises 2:

List of Noises 3:

Clicking noise 2
Clicking noise 3
Explosion sound
Grating noise
 
Question
Got a Midas B wall mounted combination gas boiler made by Mason Heating. Firstly; for no apparent reason, day or night at completely random times the boiler makes an incredible clicking sound! It appears the main burner area (from looking at the manual) is trying to ignite!? It happens not because we are turning on any hot taps; early hours of the morning just basically any time. The clicking noise can go on for a few minutes at a time - drives me mad. When the boiler is not working, the bar pressure over a few days drops from 1 bar down to zero and I have to fill the system up again to 1 bar. But the system clicks regardless if the bar pressure is low. Another hick-up as well. In the morning I have a great hot shower, a few minutes later my wife will have a shower but there is no hot water?! I have to go and turn the central heating on and the kitchen sink taps to try get the burner to ignite and supply the shower with hot water. The first shower is always ok, but 6 out of 10 times the second shower is the problem.
Another problem. We have a second bathroom about twenty feet away from the boiler which has just a bath. The pressure out the hot tap is not very good plus the hot water is not very hot. By the time the bath is full it just got hot water in so the temp does not require cold water - same goes for the vanity hot tap? Kitchen hot water tap has the same issue.
I know that Mason no longer make boilers and Baxi took them over.
Anyway, hope someone has some good news or advice for me.

Answer
Clicking will be an intermittent electrical problem, possibly a bad solder joint on a pcb, or dirty relay contacts.
Poor hot water performance is usually caused by build-up of sludge, typically in the primary side of the secondary (HW) heat exchanger ( & maybe main heat exchanger too at this age - boiler sings?). This results in low HW temperature for the flow, and overheating of the boiler. It can't get the heat out so it overheats and shuts off until it cools down. Meantime no hot water at all.
Low temp at particular outlets is due to the above, plus too high a tap flow rate for the amount of energy getting into the water - it just comes out too "diluted" = cool. We shower at 38-40 but bathe at about 45.
First problem needs inspection and maybe new parts, sludge can be removed with special methods/machines/chemicals.
Oh - the other problem, losing pressure. It's leaking, in it! Look at the pressure relief pipe which goes out through the wall. Quite often they leak (drip) a bit. That would be because either the valve seat is dirty , or the pressure vessel needs pumping up. (if there's no "air-spring" for the expanding water to go into, it has to leak out). Other places to look for leaks are red valve stems and compression connections.

If you've been topping up for long with hard water, you've been introducing "lime scale" and fresh oxygen to the heating water which will accelerate sludge formation.
Most combos with these problems were put in on the cheap and haven't been serviced this century!!
                                                                                                                                                                         
Question
"Explosion ignition" and high bar pressure during use.
System Saunier Duval System 400 (25 year old Combi boiler)
Boiler has been making a loud thudding whoosh sound which rattles the case when firing back up during normal use. I think they call it "explosive ignition"
The Boiler was serviced by British Gas a few days ago. He told me this was normal. I think the ferocity of the whoosh and rattling of internals has increased since he balanced the radiators. More heat from all 12 radiators and better running system.
The boiler pressure in bars goes from 1 to 4. It's just below 1 before turning on and slowly creeps up to just under 3 in about a hours time of use. Is this normal?

Again, the British Gas engineers said the system was fine and signed off the service.
My knowledge and understanding has come from using Google over last few days (I'm by no means an expert) and the same things terms & answers seem to come up.
I.e. you shouldn't see a big increase in pressure during use, explosive ignition problem is not normal and needs checking. The filling loop needs to be disconnected. And loss of charge/pressure in expansion vessel can cause rise in pressure.
Does anyone see a pattern here? I would like to call a local engineer to fault find this and would like some background knowledge to ask questions.

Feedback
New ignition system installed. A click before the gas fires back up and silence. Operating for 2hrs and no loud clatter. Can't believe how quite the operating noise is...
Good thing about the internet and forums like this is that you can push the Engineer to fix problems... with some basic understanding and examples.
This engineer was a good lad though his enthusiasm to investigate the problem wasn't there at the start but he did prevail. Maybe British Gas aren't that bad hahah
Also no extra cost for time fixing and component. This was a continuation of a paid 'service' to the boiler.
                                                                                                                                                                         
Question
Recently my boiler (Baxi Solo 2 model 40) started making something of a loud grating noise when firing up, which continued as the boiler ran, and ran down within a few seconds of the boiler switching off (actual boiler
operation is fine, BTW).
This volume of this noise has since reduced, and now sounds very much like a moaning-grating noise, but is *fairly* quiet.
I've had the carcass off the boiler to take a peek inside, and the sound seems*1 that the sound is coming from the fan unit (unit is described as "fan assisted" - I guess that means a powered flue?).
One thing I noticed is that on top of what I'll call the "blower" - an encased cylindrical unit that I assume holds the hot fan, there's the exposed drive motor, and a small pressed steel fan blade, presumably a secondary fan to keep the motor cool. If that is rotated by hand it actually lightly fouls the "blower" assembly. This in itself is not enough to cause
the noise, but might be indicative of a bearing collapsing, resulting in the shaft being off-centre.
One further observation, it's getting hot around the blower unit - to the extent where plastic shrouds around electrical terminals are disintegrating.
So, quick questions:

• Does this indeed sound like a fan/blower failure.
• If so, is this a DIY or professional job?
• If DIY, typical cost of a fan unit? (all I can get ATM are details of places, not prices, and I need to diagnose the problem 1st)
• On a 7 year old boiler, is a replacement unit more practical?
• If I was to replace boiler WITH LIKE, installation / commissioning charges likely from a Corgi?

Feedback
Okay, since the reply to date suggested that the fan is a consumable, I've had the unit apart and sprayed some PTFE lubricating oil on the motor, fan and blower bearings; now, quiet as a lamb. Will wait to see if this is a temporary fix before deciding to replace the fan unit.                                                                                                                                      

List of Noises 4:

Grinding noise 1
Grinding noise 2
Plane engine noise
Squeaky noise

Question
My boiler sounds like a 737 landing, ok maybe a 727.
Moved into my current house a 1960’s 3 bed detached house, about 18 months ago. It has an open vent, fully pumped heating system with a Glowworm Economy Plus 60F.
The pipe work seems a little strange with 22mm from boiler to upstairs and 10mm off to rods with TRV’s; it then drops in 15mm to feed the hall and lounge. I have altered the controls as it only had a single 2 way valve installed? an old electro-mechanical timer and no room thermostat.
I have updated the controller now a Siemens RWB2E (alright I know, but it works for me), and installed a second 2 way valve, along with a room stat and a new cylinder stat. This now all operates fine, on/off at right time and hot water only as required.
However, it has been making some noise dependant on where the boiler thermostat is set, I called British Gas under the service contract and the engineer suggested that the noise might be due to scaling, he inserted some cleaner into one of the rads and said to leave it to work through. The noise continued with a grinding sound, which seemed to be linked to the fan, BG replaced the Fan, which did seem to calm the noise a little.
However just before Christmas the noise became quite loud, BG turned out and the engineer suggested that improving the flow might help, he removed the Grundfos Alpha pump and find a standard pump set to maximum. He did conclude that any further noise must now be the heat exchanger, which was a discontinued part for this model.
The boiler thermostat is now set to minimum, above which there is significant noise.

I have checked a few spare suppliers and the heat exchanger does seem to be available, can I insist that BG change it under the service contract? Is there any way to prove the noise is related to circulation and or sludge in the heat exchanger?

Answer
You could try a bottle of silencer but I've had mixed results. Cheaper than a h/e or a new boiler though so maybe worth a gamble.

Feedback
Firstly, put in a second bottle of F2 and it has worked perfectly. Boiler now operating very quietly, I have been able to turn the pump down.
I am still planning to put in the DX40, but hopefully this can wait until the warmer weather when I can lockdown the rods for a week. At same time I will detach rods and take a hosepipe to them.
                                                                                                                                                                          

Question
Background:
Potterton Netaheat 30 boiler open vented system
Grundfos Selectric 15 50 pump
Drayton controls incl Drayton mid position valve
When the Potterton is on control setting 1 it all works fine, but if the temperature drops down to the -5 degrees outside, the boiler can struggle to keep the house at 21 degrees. Therefore increase Potterton to 3 and when it all fires up, the Grundfos pump draws in air and makes a horrible grinding noise. Air can be heard circulating round system for a bit. The open vent pipe is 2m in height so tall enough I understand not to be drawing air in, though not had a chance to try the pint glass test yet.
Seems like it's the boiler causing the problem, but I don't yet understand what it's doing or what is causing it.

Answer
Second picture down will be where the problem is. Called the H section just above the pump and will be restricted in that area. Needs cutting out and cleaning. Blockage usually in 15mm cold feed.
                                                                                                                                                               

Question
We woke up this morning to a grinding, squeaky noise coming from our old "Fer Industry" Combi boiler and no heating or DHW. Upon taking the cover off it appeared that the noise was emanating the fan in the top right hand corner (see pics with red arrow pointing to part). The little fan associated with the motor there was turning intermittently at best but the solenoid associated with it is humming constantly. I hovered the dust around it and put a few drops of oil as close to the axle as I could but there was no improvement.
Can someone please tell me:
Is this indeed a fan associated with the flue? Are they easily taken out and inspected? Can I do this myself as someone who regularly does a bit of DIY? Or should I ask a plumber to switch the fan for a new one? How much can I expect to pay for that?
Any other advice on how to properly diagnose the problem and potentially fix it. Our flat is on the market and I'd rather not invest in a new boiler!

Feedback
I looked up the fan with a plan to purchase it but just before payment I figured I might as well make a last ditch attempt at fixing the problem by removing the old fan, taking it apart, cleaning it (you wouldn't believe the pile of dust I extracted from it!) and oiling everything in sight. That seems to have done the trick as the boiler is now running like a dream and much quieter than even before the fan seized. Thanks for all the help!                                                                            

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